1. Field of the Invention
The present invention relates to a method for assembling rolling members, a rotary member, a process cartridge and an image forming apparatus. The image forming apparatus may be, for example, an electrophotographic Copying machine, a facsimile machine, a laser beam printer, an LED printer, a word processor and the like. Further, the rotary member is rotated during the image forming operation and may be, for example, a photosensitive drum as an image bearing member, an insulation drum, a developing sleeve as a developer bearing member, a charge roller as a charge means and the like.
2. Description of the Related Art
In an image forming apparatus such as a printer, a latent image is formed on an image bearing member by selectively exposing the uniformly charged image bearing member. The latent image is visualized as a toner image and the toner image is transferred onto a recording medium, thereby recording the image. In such an image forming apparatus, since the maintenance of various elements can be performed only by expert servicemen, the users experienced inconvenience. To avoid such inconvenience, there has been proposed a process cartridge wherein the image bearing member, charger, developing device, cleaning device and the like are integrally assembled as a unit which can be removably mounted to an image forming apparatus by the user and which can be exchanged by a new one when the toner is used up or the service lives of the image bearing member and the like have expired, thereby facilitating maintenance.
Such a process cartridge is required to be made small-sized in correspondence to the requirement of the compactness of the image forming apparatuses. To this end, sliding bearings have been used as bearings for rotary members such as the image bearing member (for example, a photosensitive drum) and a developer bearing member (for example, a developing sleeve). However, when the process cartridge is mounted to the image forming apparatus and then is driven, a great torque is applied to the rotary members such as the image bearing member and the developer bearing member. Thus, when such rotary members are supported by the sliding bearings, since the sliding resistance of the rotary member being rotated is great, a great load is generated. Accordingly, in order to drive such rotary members, a large motor capable of generating great torque is required, thereby making the image forming apparatus more expensive.